Taz Pro Homing Issue

Hi all:

I’ve got a Taz Pro I inherited at work that just started having a homing issue. There’s no clear cause of this issue.

When homing the Y-axis, the printer runs into the Y axis, then starts vibrating loudly - almost like the sensorless homing is failing to engage.

Video: Lulzbot Taz Pro Homing Issue - YouTube

I’d love to hear any recommended solutions. I have tried:

  • Increasing bump sensitivity, all the way to its max at 63
  • Increasing motor current (up to 1070mA)


For the drivers used on the Pro, +63 is the lowest sensitivity, -64 being the highest senstivity.
TMC Bump Sensitivity | Marlin Firmware (marlinfw.org)

Mine is set to +6 and 975mA on both X and Y axes.

And it typically only takes a click or two down from the default value to fix this issue.

Sensitivity might be a bad name for it. It is more like a trip level, so lowering the number makes it detect the bump easier. If you lower it too much, you can get inaccurate homing because it can detect a bump when it hasn’t actually hit the end yet, especially if the bed gets harder to move toward the ends of travel.

@Wrathernaut @cdsmith

Thanks for the help. Lowering the bump sensitivity to +5 fixed the issue!

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